Engine starting assembly



Sept. 11, 1934. F, D BUTLER 1,972,867

ENGINE STARTING AS SEMBLY Filed Nov. 4; 1931 2 sheets-sheet 1 l 54' 1@ 7.7 Q5 l5 I8 l 413,7 ,455 28 V ATTORNEY Sept. '11, 1934.

F. D. BUTLER K ENGINE STARTING ASSEMBLY Filed Nov., 4, 1951 2 sheets-sheet 2 lNvENToR ATTORN EY Patented Sept. 11, 1934 ENGINE STARTING ASSEMBLY Frank David Butler, United States Navy, Bremerton, Wash.

Application November 4, 1931, Serial No. 573,009

21 Claims.

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 G. G. 757) While my invention relates generally to engine starting assemblies, it relates more particularly to improvement in means for starting combustion engines and has the following objects in view: First, to provide a safe and practical starter for starting high powered combustion oil or gas engines without the usual danger of injuring either the starting personnel or the starting device, and that will not require an exorbitant physical or mechanical source of power for the proper operation of said device; second, to provide suitable means for properly engaging and disengaging the driving member with and from the driven member of the starting assembly respectively; third, to provide means of utilizing the driven member of the starting assembly as a combustion impulse shock absorber or engine vibration dampener; fourth, to provide a suitable means of retaining the driving member of the starting assembly out of mesh with the driven member while the latter is not in use for starting purposes; and finally, to produce a starting assembly design of the type mentioned which is exceedingly simple in construction, erlicient and safe in operation, durable in use, and which may be readily and conveniently applied to the various types of engines.

Two of the many possible embodiments of my invention are illustrated in the accompanying rawings, in which:

Figs. l to 3 inclusive illustrate one of the embodiments, and Figs. 5 to 8 inclusive a modified embodiment;

Fig. l is a fragmentary view of an engine with my starting assembly applied thereto as it could be operated with a mechanical appliance, the assembly being illustrated as would appear on the dotted and broken line A-A of Fig. 2;

Fig. 2 is a longitudinal section as would appear on the dotted and broken line B-B of Fig. 1;

Fig. 2 is similar to Fig. l except that it illustrates the starting assembly as it could be operated with a manual in place of the mechanical appliance;

Fig. 4 is an enlarged section in detail of the drive member engaging device which is also illustrated in the assemblies Figs. 1, 3 and 5;

Fig. 5 is a fragmentary View of an engine and illustrates the mcdied embodiment of my invention as it would appear on thedotted and broken line C-C of 7; Y

Fig. 6 is an enlarged fragmentary detailed view of a portion of Fig. 5 and also as would appear on the dotted and broken line D-D of Fig. 8;

Fig. l is a sectional view as would appear on the dotted and broken line E-E of Fig. 5; and,

Fig. 8 is an enlarged fragmentary view of a portion or" Fig. 'l and illustrates a small section of the driven member assembly in-detail.

'With reference to the symbols of the drawings, similar nii-.merals and letters represent and indicate similar parts in the 'several views, the numeral 1 indicates the engine crank shaft, having one or more crank pins 1a and which is mounted and adapted to rotate in suitable bearings (not illustrated) in the usual manner, the numeral 2 indicates the driven or worm wheel member which is adapted to be mounted on the crank shaft 1 in a rotatable manner, said member 2 being equipped with the anti-friction bearing member 3 or With a suitable roller bearing unit 3d. The numeral 4 indicates suitable fibrous friction clutch linings or members which are adapted to be mounted in suitable recesses 4a disposed in the side faces of said driven member 2, said clutch linings 4 being adapted to operate in conjunction with the friction clutch surfaces of the rigidly secured clutch disc 5 and the adjustable clutch disc 6, said discs 5 and 6 being suitably mounted on either side of the member 2 and being adapted to be keyed so as to rotate with the crank shaft by the keys '7V and '7a respectively, the desired friction between said discs and said linings being produced by the clutch tension spring 8 which latter may be manually adjusted by changing the adjustment of the threaded spring retainer collar 9 and itsretainer jam nut l0.V

With reference to Fig. 3, the drive or Worm member 11 is illustrated in mesh or, engaged with the driven or worm wheel member 2, while in Fig. l said worm member 11 is illustrated out of mesh Vor disengaged from said Worm wheel member 2. In the liirst mentioned figure said worm member 1l is illustrated as being adapted to be rotated manually by the crank lever 12 while in the last mentioned iigure and also in Fig. 5 said Worm member is illustrated as being adapted to be rotated mechanically by the electrically operated starting motor 13 or manually by applying the crank lever in the manner illustrated by the dotted outlines `of saidcrank lever 12. In both the manually and mechanically operated installations mentioned and illustrated, the .drive worm member 11 is ,adapted -to :be a sliding fit on the splinedshaft 14 which latter is mounted in the journal members 15 and 16, said last mentioned members being in turn suitably mounted to rotate in the starter housing or casing 1'7,A the latter having integral therewith the suitable shoulder 18 which is adapted to receive the thrust of bearing 19 which latter is mounted loosely on the shaft 14 and is adapted to take the engine starting thrust of said worm member ll. In addition to its splined fit to the shaft le, the worm member 1l consists of, a worm threaded portion 20 which latter is tapered ofi at its engaging end and shouldered at the opposite end thereof and is adapted to be a mesh iit with the teeth 21 of the worm Wheel 2, an annular shaped retainer lock groove 22 which is adapted to operate in conjunction with the spring loaded retainer pin 23 in preventing said worm from sliding into mesh with the teeth 2l of the worm wheel 2 during the period the cranking or starting device is not in use, a tapered portion 2li' which is for the purpose of preventing the retainer pin 23 from being. lifted too abruptly during the period said worm is being. disengaged from the teeth 2l of said worm wheel 2 (which latter operation will be described later), and the cylindrical shaped collar or shoulder 25 which is adapted to operate in conjunction With-the dash pot cham.- ber 26 in cushioning said worm in its longitudinal .travel during the period it is being disengaged from the teeth 21 of saidy worm wheel 2.

VThe. -previously mentioned retainer pin. 23 is mounted in the casing 17 and consists of the shoulder portion 27' which latter is adapted to limit the inward travel of said. pin, and the rounded end portion 28' which latter is adapted to engage the end of the worm 11 and to operate in conjunction with the previously mentioned retainer lock groove 22 in securing. said worm ll inf the out of mesh position (similar to that illustrated in. Fig. l) during the periody the starting device' isfnot in operation, said retainer being resilient in its: action due to the resilient qualities conveyed to it bythe retainer spring 29 which latter is adapted to bear against its upper end.

' During the starting rotation of the splined shaft 114-: the wormA l1 is moved from the position illustra-ted in Fig. l to the position illustrated in Fig. 5 and is brought into mesh or engaged with the teeth 21 of the worin wheel 2 by a suitable ball' andY socket worm engaging assembly which latter consists of the engaging ball bearing 30 which is mountedY in the ball socket member 3l which latter is mounted in the casing. 17 and to be held. in contact with said ball 30 by the resilient qualities of theY tension spring 32' which latterii'n turn is adapted to' be'properly adjusted by means of the adjusting screw 33 and its lock nut 341 During said starting rotation of the splined shaft the ball bearing 30 is forced into mesh with the threaded portion 20 of the worm 11 by the resilient tension of spring 32 and is thereby compelled to act in the capacity of a nut andv to yieldably `advance or feed the worm 1l towards'the worm wheel 2, the retainer pin 23 being lifted in the meantime from the groove 22 due to the spring 32 having a stronger tension than spring 29.

The tapered threaded end of worm 1I which rst enters into mesh withy the worm teeth 2l is adapted tofacilitate their intermeshing as worin .the spiral tooth or teeth on worink 1l in progressive relation to said tooth 21 until said Worm teethr intermeshr, the Vbal'l'ilyieldinglto prevent forcing the longitudinal-movement lof worin llY until the worm teeth intermesh. This automatically prevents the worrn teeth interlocking and breaking.

This movement of worm l1 tangentially to the periphery of Worm teeth 2l also preventsthe eX- pensive necessity of tapering the entrance edges o1" teeth 21 where the starter pinion (in lieu of worm 11) moves longitudinally by a positive screw into starting mesh, as in the prior art.

Once the threaded portion 20 of the worm ll enters mesh with the worm wheel teeth 21 (as illustrated in Fig. 5) said teeth 21 relieve or cooperate with the ball bearing 30 in its capacity as a nut and continues the feeding operation by drawing said worm 1l further into rnesh until the end of said Worin comes in contact with Athe thrust bearing l9 (as illustrated in Fig. 3) at which time all further advancement of the worm ll towards theworm wheel 2 is discontinued and any further rotation of the shaft 14 would cause the worm wheel 2 and the engine crank shaft l to rotate in the direction indicated by the arrows F of Figs. l, 3 and .5. As the rotation of the shaft 14 is continued and the engine starts to rotate and develop its own rotative power, the worin ll is forced out of mesh with the teeth 2l due to the power rotation of the worm wheelv 2 at a higher rate of speed than it is adapted to be driven by worin 1l, the ball bearing 30 in the meantime acting in the capacity of a snubber by assisting in reducing the longitudinal acceleration of said worm ll as it is rapidly forced away from the wheel 2, said ball 30 being assisted in. reducing the longitudinalv acceleration of said worm ll (as it nears the position in which it is illustrated in Fig. l) by the air cushioning eifect of the cylindrical portion 25 entering the dash vpot 26, and the further'snubbing effect oi the retainer pin 23 passing over said portion 25 into the annular shaped retainer groove 22', the final out of mesh position reached by said worm ll being the position in which it is illustrated in Fig. 1.

In the event the engine should back-fire while it is being started and a retrograde motion of the crank shaft set up thereby, no damage would result therefrom due to the fact that the clutch linings 4 would' slide on the friction surfaces of the discs 5 and 6 and would allow the worin wheel 2 to continue to rotate in the correct starting direction, while inthe meantime the friction set up by the sliding of the linings 4 over said friction surfaces of said discs would cause a braking eiieot that would tend to counteract said retrograde motion of said crank shaft andv would l force said shaft to stop rotating and to then restart in the proper direction.

The worm ll and the teeth 2l (at least) of the worm wheel 2 should be manufactured of a suitable metal kor metal alloy that may be heat treated or hardened so that in the event the starteris accidently rotated, (while the 'engine is in operation) that no damage will result to said Worm and teeth, the action of the latter during such an accident would be to continually prevent, by yielding ball 30 and by teeth 2l repelling worm l-l, said worm from entering mesh therewith by forcing said worm towards its safety lock position (in which it is illustrated in Fig. l) each time it approached the rim of the worm wheel 2.

In order to utilize the driven member of the engine starter assembly in the capacity of an enginevibration dampener, the said driven member or in reality the worm wheel `2 is flexibly mounted between the clutch linings 4in the following manner: Two prospective embodiments of the installation of the flexible means in the worm wheel 2 are illustrated, Figs. 1 to 3 inclusive showing one method of applying said flexible means and Figs. 5 to 8 inclusive illustrating the other method. In both embodiments the fibrous clutch linings 4 are adapted to bear against the outer ends of suitable rubber inserts 35 which latter are mounted in suitable countersunk holes 36 which are disposed in the sidD faces of the worm wheel 2, the latter being thus flexibly suspended between said linings 4 bybeing mounted on said rubber inserts 35, said inserts furnishing the medium of rotative power conveyance between said worm wheel and said clutch linings and vice versa. In the former group of figures suitable rivets 37 are used to clamp the clutch linings 4 in -contact with the ends of the rubber inserts 35 for the purpose of preventing said linings from sliding on the ends of said rubber inserts, while in the latter group of figures the rubber inserts 35 are cupped at their ends as per numeral 33 in order to accomplish a similar purpose. In both groups of figures the countersunk holes 36 are illustrated as being practically uniform in diameter throughout their lengths, and as extending throughout the width of the worm wheel 2, it being apparent and understood, however, that said holes could be made of any other convenient or desirable shape and as well serve the object of the holes 36 and the rubbei' inserts 35 to support and suspend the worm wheel 2 midway between the clutch linings 4 in a most efficient and practical rotatably flexible manner. It is to be further understood that the clutch linings 4 are not intended to slip either on the ends of the rubber inserts 35 or on the friction surfaces of the clutch discs 5 and 6 during the period said driven member of said engine starter assembly is acting in the capacity of an engine vibration dampener; it being also understood that the rotatable flexibility of the driven member 2 would assist in preventing the teeth 21 of said member 2 from fouling the Vthreaded portion 20 of the worm 11 as the latter was in the act of meshing with or engaging the teeth 21 during the starting operation of the engine. The operation of the engine vibration dampener feature of the engine starter assembly is as follows: When for any reason the rotation of the crank shaft is irregular (such as during the combustion impulse periods of a combustion engine) the tendency of the worm wheel 2 is to continue at a regular rotative speed and as said crank shaft suddenly and momentarily increases or decreases in rotative speed said worm wheel (due to its flexible mounting as previously described) tends to counteract such irregular rotative motion by sagging behind as the crank shaft increases and forging ahead as said shaft decreases its rotative speed, the result is, a greater number of rotative vibrations of far less magnitude, and a smoother operating engine than would be the case if the worm wheel l2 was rigidlysecured to the crank shaft 1.

The following are a few details relative to the construction of the starter wsembly. In the securing and adjustment of the discs 5 and 6, it is necessary that at least one of said discs be acljustable in order to take up clutch surface wear, that both of said discs be secured either directly or indirectly to rotate with the crank shaft 1, that provision be made similar to the shim 39 (Fig. 2) or the force screw 40 and draw bolt 4l (Figs. 5 and '7) for the purpose of adjusting the worm wheel'2 to proper alinement'with the shaft 14, and that said discs be adjusted 'only sufficiently tight to properly rotate the crank shaft during the engine starting period of operation. Spring snap rings 42 are used wherever possible to retain the various parts of the assembly to the proper limits of their respective travel.

The starter gear 11 being liable to substantial service wear and replacement is adapted to become, with its predecessors, an article of manufacture subject to substantial demand.

The invention herein described may be manufactured and used byor for the Government of the United States for governmental purposes without the payment to me of any royalty thereon or therefor. Y

Having fully described my invention, what I claim as new and desire to secure by Letters Patent is:-

1. In an engine starter assembly, the combination with the crank shaft of the engine tobe started, of a driven worm gear-"on said shaft, a rotatable shaft mounted at right angles to said crank shaft, a driving worm mounted slidably on the rotatable shaft and adapted to mesh with the driven worm gear, a yielding lmember for producing longitudinal movement of the driving worm gear upon the rotation of said rotatable shaft, means for flexibly mounting the driven Worm gear on said crank shaft, andmeans for snubbing and cushioning said driving worm as it is forced to slide longitudinally on said rotatable shaft by the rotary disengaging force of said driven worm gear as said engine accelerates under its own power.

2. r)The combination of claim 1 characterized by a housing provided with a cavity open at one end and into which the driving worm moves when unmeshing; said drivingworm having, on its end most remote from the driven worm gear when unmeshed therefrom, a peripherical recess whose marginal edges are adapted to engage the wall of thecavity; and a yielding member comprising a yieldingly mounted securing or locking device having a limited movement and extending into said cavity and engaging the driving worm for yieldingly retaining the driving worm gear in its unmeshed position.

3. The combinationr of claim 1 embodying a resiliently mounted retainer means for securing said driving worm in its out of mesh position of travel during the period it is not in use.

li. The combination of claim l wherein said driving worm comprises a helical toothed periphery adapted to mesh with worm teeth dis- 12S' posed on the outer periphery of said driven gear, the driving worm being also'adapted to engage said yielding member, the teeth of the driving worm being tapered at the end adapted to enter into mesh with the teeth of the driven worm gear, said snubbing and cushioning means comprising a cylindrical shaped plunger portion ydisposed at the opposite end of the toothed portion of the driving worm and being adapted to operate in con- Y f 5. The combination. of claim 1 embodying a bearing support for the rotary shaft, said support having a recess, said yielding member comprising a ball mounted in said recess, a spring exerting stress on the ball, and means for adjusting the tension of said spring'.

6. The combination of claim 1 wherein said means for snubbing and cushioning said driving worm gear comprises a plunger portion of and disposed near the outer end of said driving worm, a cushioningdash pot chamber adapted to receive said vplunger portion in the disengaging travel of said driving worm, and a snubbing friction yieldingly mounted retainer engaging said plunger portion andV securingv the driving worm in its disengaged position.

7'. The combination of kclaim 1 wherein said yielding member is positioned to engage with the driving worm when out of mesh with the `driven worm gear and adapted to act inthe capacity of a nut for advancing said driving worm gear into mesh with said driven wormV gear during the engaging operation of the starter, and to act in the capacity of a snubber for the purpose of retarding the longitudinal velocity of travel of said driving worm during disengagement.

8. The combination of claim 1 wherein said flexible mounting of said driven worm gear comprises a pair of clutch discs rotating with said crank shaft, one on each side of said driven worm gear, a clutch lining intermediate said discs and the side faces of said driven vworin gear, a plurality of holes in said driven worm gear, a plurality of-llexibleA elements, one in each of said holes and positioning said driven worm gear between said clutch linings, and means for adjusting the friction tension between said discs and said clutch linings, the'clutch discs allowing the driven worm gear movement independent of the crank shaft when the engine back-fires while being started. l

9. The combination in a combustion engine starter assembly of a driving shaft adapted to be rotatably mounted at right angles toy an engine rotatable member that is to be started, a driving worm keyed to andv longitudinally slidable on saidV driving shaft, yieldingly mounted means adapted to mesh with the toothed portion of said driving worm to cause said driving worm to automatically'engage and drive said engine rotatable member during the initial starting rotation of said drive shaft, yielding means cooperative with anl annular grooved portion in the periphery of a portion of said driving worm for retaining the latr in its disengaged position, and means'for rotating said drive shaft.. n

10. In a combustion enginestarter assembly, a driving worm having a straight splined bore adapted to slidingly t on astarter drive shaft,

` said driving worm also having a toothed periphery adapted to mesh with the teeth of a driven wormgear and the teeth of said periphery being `adapted to be engaged by a yieldingly mounted ball for longitudinally moving the driving worm during its rotation into mesh with' the teeth of the driven worm gear and the driving Worm being provided with a projection having an annular recess and an inclined wall at the end of said projection, said wall being adapted to ent'er a dashpot and be engaged by a detent for holding the driving worm gear in its unmeshed position.

11. In an engine starter the combination of an. engine shaft, a helically toothed gear, adjustable frictionmeans for drivingly connecting said gear and shaft, a starter shaft revolubly mounted at a substantial angle to the axis of said gear, a helically toothed startergear feathered to and free to slide on said starter shaft into and out of mesh with the teeth of said first gear, bearings for said starter shaft one of which abuts one end of the starter gearV when in full mesh with the rst stated gear, a cylinder surrounding the starter shaft and of a diameter snugly receiving the end of the starting gear opposite its said abutting end yin the unmeshed position of the starting gear for forming an air cushion in said cylinder by the rapid unmeshing of the starting gear, and means yieldablyV engaging the teeth of the starter gear to cause its rotation to move the Starter gear into mesh with the first stated gear and for snubbing the starter gear in its unmeshing movement.

12. 'Ihe combination of claim 11 wherein the leading ends of the teeth of the starter ygear are tapered, and a rigid bearing for the starter shaft against which the starter gear longitudinally unyieldingly exerts a thrust while starting the engine.

13. The combination of claim 11 including a rigidY bearing for the starter shaft, .and a thrust bearing assembly surrounding the starter shaft and abutting said bearing and against which assembly the starter gear longitudinally unyieldingly exerts a thrust while starting the engine.

14. The combination of claim 11 including a crank, and means for connecting said crank to an end of the starter shaft for manually driving the starter shaft.

15. The combination of claim 11 including a starting motor having a shaft, andacoupling removably connecting said starter shaft to the motor shaft.

16. The combination of claim 11 including a starting motor having a shaft adapted to drive the starter shaft, a crank, and means forremovably'attaching said crank to an end of Asaid motor shaft to manually rotate said starter shaft.

17.'As an article of `manufacture for engine starters, a helically toothed starter gear having a substantial width of toothed periphery with the leading ends of the tooth or teeth tapered, said teeth being adapted to mesh longitudinally of the starter gear, but be normally out of mesh with a driven gear, and the end` adjacent said taperedtooth or teeth being adapted to bear -f against a thrust bearing while starting the engine, and the bore of said starter gear having a longitudinal keyway kupon which the gear is adapted to slide into and out of mesh with, and

at a substantialangle to, a driven gear, and the end of said starter gear opposite said thrust bearing end being cylindricaland having a continu-- ous end wall vof a diameter of at least that of said toothed periphery. Y

18. The article of claim 17 wherein the end --1 v' 0f starter gear opposite the bearing end is adapted to actas a piston when the starter gear is moved in its unmeshing movement, said piston end having on its periphery a plurality of spaced apart ringswhich, with said end wall, are adapted to compress a fluid upon said unmeshing movement, and the grooveV between said rings being adapted to be engaged `by a retainer. y

19. In a combustion engine starter the combination of astarting means, a part rotatable i with the engine, gears intermediate said means vand part and adapted to bein mesh to start the engine, friction driving means connecting one of said gears to its rotatable element for accommodating without injury the shocks of back firing While starting the engine by said starting means, a housing enclosing said gears and friction means, one of said gears being longitudinally movable Within said housing and out of mesh With its associate gear, and said housing having a cylinder closely conning an end of the longitudinally movable gear in its unmeshed position and adapted to form a fluid cushion in said unmeshing.

20. The combination of claim 19 wherein said friction means comprises a friction clutch clutching one of said gears -to rotate with its rotatable element, the force of said clutching being adapted to admit of starting the engine and to slip when subjected to the shock of backring while starting the engine by said starting means, and means for adjusting the force with which said clutch clutches said gear.

21. In an engine starter the combination of starting means, a shaft adapted to be driven by said means, a gear feathered to and slidable on said shaft, an element rotatably connected to the engine and having its axis at a substantial angle to the shaft, a second gear supported by said element and With which the feathered gear meshes when starting the engine, a plurality of friction members rotatably fixed to the element and drivingly engaging the second gear; means for applying spring pressure to at least one of said friction members, whereby the engine may be started through said frictional driving engagement which harmlessly accommodates backring; a housing enclosing the feathered gear and a portion of said shaft and having separated bearings for said shaft, a thrust bearing surrounding said shaft and supported by said housing and adapted to engage the outer end of the feathered gear when in mesh with the second gear; said housing having a cylinder; and a piston head movable with the feathered gear and adapted to closely fit, and form a fluid cushion, in the cylinder When the feathered gear is returned -to its unmeshed position.

FRANK DAVID BUTLER. 

